Imagine you are a scientist observing rats in the wild. As the rats reproduce, rats born with white fur slowly begin to outnumber rats with black fur. In three to five sentences, provide two or more different explanations of why the rats with white fur might be outnumbering the rats with black fur.

The gene that causes sickle-cell disease is present in a higher percentage of residents of sub-saharan africa than among those of african descent living in the united states. even though this gene causes sickle-cell disease, it also provides some protection from malaria, a serious disease that is widespread in sub-saharan africa but absent in the united states. discuss an evolutionary process that could account for the different percentages of the sickle-cell gene among residents of the two regions.

Why do carbohydrate molecules function so well as fuel for the body?

Which of the following types of stars are dim but can have high surface temperatures? giants main sequence stars supergiants dwarfs